text: /*
   * Copyright 2015 Robert Foss. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * - Redistributions of source code must retain the above copyright
   *   notice, this list of conditions and the following disclaimer.
   * - Redistributions in binary form must reproduce the above copyright
   *   notice, this list of conditions and the following disclaimer in the
   *   documentation and/or other materials provided with the
   *   distribution.
   * - Neither the name of the copyright holders nor the names of
   *   its contributors may be used to endorse or promote products derived
   *   from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
   * THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
   * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   * OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * @author Robert Foss <dev@robertfoss.se>
   *
   * Additions & fixes: Johny Mattsson <jmattsson@dius.com.au>
   *                    Jason Follas <jfollas@gmail.com>
   */
  
  #include "module.h"
  #include "lauxlib.h"
  #include "lmem.h"
  #include "platform.h"
  #include <stdlib.h>
  #include <stdio.h>
  #include <string.h>
  #include "ctype.h"
  #include "user_interface.h"
  #include "espconn.h"
  #include "lwip/tcp.h"
  #include "lwip/pbuf.h"
  #include "vfs.h"
  #include "task/task.h"
  
  /* Set this to 1 to generate debug messages. Uses debug callback provided by Lua. Example: enduser_setup.start(successFn, print, print) */
  #define ENDUSER_SETUP_DEBUG_ENABLE 0
  
  /* Set this to 1 to output the contents of HTTP requests when debugging. Useful if you need it, but can get pretty noisy */
  #define ENDUSER_SETUP_DEBUG_SHOW_HTTP_REQUEST 0
  
  
  #define MIN(x, y)  (((x) < (y)) ? (x) : (y))
  #define LITLEN(strliteral) (sizeof (strliteral) -1)
  #define STRINGIFY(x) #x
  #define NUMLEN(x) (sizeof(STRINGIFY(x)) - 1)
  
  #define ENDUSER_SETUP_ERR_FATAL        (1 << 0)
  #define ENDUSER_SETUP_ERR_NONFATAL     (1 << 1)
  #define ENDUSER_SETUP_ERR_NO_RETURN    (1 << 2)
  
  #define ENDUSER_SETUP_ERR_OUT_OF_MEMORY          1
  #define ENDUSER_SETUP_ERR_CONNECTION_NOT_FOUND   2
  #define ENDUSER_SETUP_ERR_UNKOWN_ERROR           3
  #define ENDUSER_SETUP_ERR_SOCKET_ALREADY_OPEN    4
  #define ENDUSER_SETUP_ERR_MAX_NUMBER             5
  #define ENDUSER_SETUP_ERR_ALREADY_INITIALIZED    6
  
  /**
   * DNS Response Packet:
   *
   * |DNS ID - 16 bits|
   * |dns_header|
   * |QNAME|
   * |dns_body|
   * |ip - 32 bits|
   *
   *        DNS Header Part          |  FLAGS | | Q COUNT |  | A CNT  |  |AUTH CNT|  | ADD CNT| */
  static const char dns_header[] = { 0x80, 0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00 };
  /*        DNS Query Part           | Q TYPE |  | Q CLASS| */
  static const char dns_body[]   = { 0x00, 0x01, 0x00, 0x01,
  /*        DNS Answer Part          |LBL OFFS|  |  TYPE  |  |  CLASS |  |         TTL        |  | RD LEN | */
                                     0xC0, 0x0C, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x78, 0x00, 0x04 };
  
  static const char http_html_gz_filename[] = "enduser_setup.html.gz";
  static const char http_html_filename[] = "enduser_setup.html";
  static const char http_header_200[] = "HTTP/1.1 200 OK\r\nCache-control:no-cache\r\nConnection:close\r\nContent-Type:text/html; charset=utf-8\r\n"; /* Note single \r\n here! */
  static const char http_header_204[] = "HTTP/1.1 204 No Content\r\nContent-Length:0\r\nConnection:close\r\n\r\n";
  static const char http_header_302[] = "HTTP/1.1 302 Moved\r\nLocation: http://nodemcu.portal/\r\nContent-Length:0\r\nConnection:close\r\n\r\n";
  static const char http_header_302_trying[] = "HTTP/1.1 302 Moved\r\nLocation: /?trying=true\r\nContent-Length:0\r\nConnection:close\r\n\r\n";
  static const char http_header_400[] = "HTTP/1.1 400 Bad request\r\nContent-Length:0\r\nConnection:close\r\n\r\n";
  static const char http_header_404[] = "HTTP/1.1 404 Not found\r\nContent-Length:10\r\nConnection:close\r\n\r\nNot found\n";
  static const char http_header_405[] = "HTTP/1.1 405 Method Not Allowed\r\nContent-Length:0\r\nConnection:close\r\n\r\n";
  static const char http_header_500[] = "HTTP/1.1 500 Internal Error\r\nContent-Length:6\r\nConnection:close\r\n\r\nError\n";
  
  static const char http_header_content_len_fmt[] = "Content-length:%5d\r\n\r\n";
  static const char http_html_gzip_contentencoding[] = "Content-Encoding: gzip\r\n";
  
  /* Externally defined: static const char enduser_setup_html_default[] = ... */
  #include "enduser_setup/enduser_setup.html.gz.def.h"
  
  // The tcp_arg can be either a pointer to the scan_listener_t or http_request_buffer_t.
  // The enum defines which one it is.
  typedef enum {
    SCAN_LISTENER_STRUCT_TYPE = 1,
    HTTP_REQUEST_BUFFER_STRUCT_TYPE = 2
  } struct_type_t;
  
  typedef struct {
    struct_type_t struct_type;
  } tcp_arg_t;
  
  typedef struct scan_listener
  {
    struct_type_t struct_type;
    struct tcp_pcb *conn;
    struct scan_listener *next;
  } scan_listener_t;
  
  typedef struct {
    struct_type_t struct_type;
    size_t length;
    char data[0];
  } http_request_buffer_t;
  
  typedef struct
  {
    struct espconn *espconn_dns_udp;
    struct tcp_pcb *http_pcb;
    char *http_payload_data;
    uint32_t http_payload_len;
    char *ap_ssid;
    os_timer_t check_station_timer;
    os_timer_t shutdown_timer;
    int lua_connected_cb_ref;
    int lua_err_cb_ref;
    int lua_dbg_cb_ref;
    scan_listener_t *scan_listeners;
    uint8_t softAPchannel;
    uint8_t success;
    uint8_t callbackDone;
    uint8_t lastStationStatus;
    uint8_t connecting;
  } enduser_setup_state_t;
  
  static enduser_setup_state_t *state;
  
  static bool manual = false;
  static task_handle_t do_station_cfg_handle;
  
  static int enduser_setup_manual(lua_State* L);
  static int enduser_setup_start(lua_State* L);
  static int enduser_setup_stop(lua_State* L);
  static void enduser_setup_stop_callback(void *ptr);
  static void enduser_setup_station_start(void);
  static void enduser_setup_ap_start(void);
  static void enduser_setup_ap_stop(void);
  static void enduser_setup_check_station(void *p);
  static void enduser_setup_debug(int line, const char *str);
  
  static char ipaddr[16];
  
  #if ENDUSER_SETUP_DEBUG_ENABLE
  #define ENDUSER_SETUP_DEBUG(str) enduser_setup_debug(__LINE__, str)
  #else
  #define ENDUSER_SETUP_DEBUG(str) do {} while(0)
  #endif
  
  
  #define ENDUSER_SETUP_ERROR(str, err, err_severity) \
    do { \
      ENDUSER_SETUP_DEBUG(str); \
      if (err_severity & ENDUSER_SETUP_ERR_FATAL) enduser_setup_stop(lua_getstate());\
        enduser_setup_error(__LINE__, str, err);\
      if (!(err_severity & ENDUSER_SETUP_ERR_NO_RETURN)) \
        return err; \
    } while (0)
  
  
  #define ENDUSER_SETUP_ERROR_VOID(str, err, err_severity) \
    do { \
      ENDUSER_SETUP_DEBUG(str); \
      if (err_severity & ENDUSER_SETUP_ERR_FATAL) enduser_setup_stop(lua_getstate());\
         enduser_setup_error(__LINE__, str, err);\
      if (!(err_severity & ENDUSER_SETUP_ERR_NO_RETURN)) \
        return; \
    } while (0)
  
  
  static void enduser_setup_debug(int line, const char *str)
  {
    lua_State *L = lua_getstate();
    if(state != NULL && state->lua_dbg_cb_ref != LUA_NOREF)
    {
      lua_rawgeti(L, LUA_REGISTRYINDEX, state->lua_dbg_cb_ref);
      lua_pushfstring(L, "%d: \t%s", line, str);
      luaL_pcallx(L, 1, 0);
    }
  }
  
  
  static void enduser_setup_error(int line, const char *str, int err)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_error");
  
    lua_State *L = lua_getstate();
    if (state != NULL && state->lua_err_cb_ref != LUA_NOREF)
    {
      lua_rawgeti (L, LUA_REGISTRYINDEX, state->lua_err_cb_ref);
      lua_pushinteger(L, err);
      lua_pushfstring(L, "%d: \t%s", line, str);
      luaL_pcallx (L, 2, 0);
    }
  }
  
  
  static void enduser_setup_connected_callback()
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_connected_callback");
  
    lua_State *L = lua_getstate();
    if (state != NULL && state->lua_connected_cb_ref != LUA_NOREF)
    {
      lua_rawgeti(L, LUA_REGISTRYINDEX, state->lua_connected_cb_ref);
      luaL_pcallx(L, 0, 0);
    }
  }
  
  #include "pm/swtimer.h"
  static void enduser_setup_check_station_start(void)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_check_station_start");
  
    os_timer_setfn(&(state->check_station_timer), enduser_setup_check_station, NULL);
    SWTIMER_REG_CB(enduser_setup_check_station, SWTIMER_RESUME);
      //The function enduser_setup_check_station checks for a successful connection to the configured AP
      //My guess: I'm not sure about whether or not user feedback is given via the web interface, but I don't see a problem with letting this timer resume.
    os_timer_arm(&(state->check_station_timer), 3*1000, TRUE);
  }
  
  
  static void enduser_setup_check_station_stop(void)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_check_station_stop");
  
    if (state != NULL)
    {
      os_timer_disarm(&(state->check_station_timer));
    }
  }
  
  
  /**
   * Check Station
   *
   * Check that we've successfully entered station mode.
   */
  static void enduser_setup_check_station(void *p)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_check_station");
  
    (void)p;
    struct ip_info ip;
    memset(&ip, 0, sizeof(struct ip_info));
  
    wifi_get_ip_info(STATION_IF, &ip);
  
    int i;
    char has_ip = 0;
    for (i = 0; i < sizeof(struct ip_info); ++i)
    {
      has_ip |= ((char *) &ip)[i];
    }
  
    uint8_t currChan = wifi_get_channel();
  
    if (has_ip == 0)
    {
      /* No IP Address yet, so check the reported status */
      uint8_t curr_status = wifi_station_get_connect_status();
      char buf[20];
      sprintf(buf, "status=%d,chan=%d", curr_status, currChan);
      ENDUSER_SETUP_DEBUG(buf);
  
      if (curr_status == 2 || curr_status == 3 || curr_status == 4)
      {
        state->connecting = 0;
  
        /* If the status is an error status and the channel changed, then cache the
         * status to state since the Station won't be able to report the same status
         * after switching the channel back to the SoftAP's
         */
        if (currChan != state->softAPchannel) {
          state->lastStationStatus = curr_status;
  
          ENDUSER_SETUP_DEBUG("Turning off Station due to different channel than AP");
  
          wifi_station_disconnect();
          wifi_set_opmode(SOFTAP_MODE);
          enduser_setup_ap_start();
        }
     }
     return;
    }
  
    sprintf (ipaddr, "%d.%d.%d.%d", IP2STR(&ip.ip.addr));
  
    state->success = 1;
    state->lastStationStatus = 5; /*  We have an IP Address, so the status is 5 (as of SDK 1.5.1) */
    state->connecting = 0;
  
  #if ENDUSER_SETUP_DEBUG_ENABLE
    char debuginfo[100];
    sprintf(debuginfo, "AP_CHAN: %d, STA_CHAN: %d", state->softAPchannel, currChan);
    ENDUSER_SETUP_DEBUG(debuginfo);
  #endif
  
    if (currChan == state->softAPchannel)
    {
      enduser_setup_connected_callback();
      state->callbackDone = 1;
    }
    else
    {
      ENDUSER_SETUP_DEBUG("Turning off Station due to different channel than AP");
      wifi_station_disconnect();
      wifi_set_opmode(SOFTAP_MODE);
      enduser_setup_ap_start();
    }
  
    enduser_setup_check_station_stop();
  
    /* Trigger shutdown, but allow time for HTTP client to fetch last status. */
    if (!manual)
    {
      os_timer_setfn(&(state->shutdown_timer), enduser_setup_stop_callback, NULL);
      SWTIMER_REG_CB(enduser_setup_stop_callback, SWTIMER_RESUME);
        //The function enduser_setup_stop_callback frees services and resources used by enduser setup.
        //My guess: Since it would lead to a memory leak, it's probably best to resume this timer.
      os_timer_arm(&(state->shutdown_timer), 10*1000, FALSE);
    }
  }
  
  
  /* --- Connection closing handling ----------------------------------------- */
  
  /* It is far more memory efficient to let the other end close the connection
   * first and respond to that, than us initiating the closing. The latter
   * seems to leave the pcb in a fin_wait state for a long time, which can
   * starve us of memory over time.
   *
   * By instead using the poll function to schedule a hard abort a few seconds
   * from now we achieve a deadline close. The downside is a (very) slight
   * risk of dropping the connection early, but in this application that's
   * hidden by the retries on the JavaScript side anyway.
   */
  
  
  /* Callback on timeout to hard-close a connection */
  static err_t force_abort (void *arg, struct tcp_pcb *pcb)
  {
    ENDUSER_SETUP_DEBUG("force_abort");
  
    (void)arg;
    tcp_poll (pcb, 0, 0);
    tcp_abort (pcb);
    return ERR_ABRT;
  }
  
  /* Callback to detect a remote-close of a connection */
  static err_t handle_remote_close (void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
  {
    ENDUSER_SETUP_DEBUG("handle_remote_close");
  
    (void)arg; (void)err;
    if (p) /* server sent us data, just ACK and move on */
    {
      tcp_recved (pcb, p->tot_len);
      pbuf_free (p);
    }
    else /* hey, remote end closed, we can do a soft close safely, yay! */
    {
      tcp_recv (pcb, 0);
      tcp_poll (pcb, 0, 0);
      tcp_close (pcb);
    }
    return ERR_OK;
  }
  
  /* Set up a deferred close of a connection, as discussed above. */
  static inline void deferred_close (struct tcp_pcb *pcb)
  {
    ENDUSER_SETUP_DEBUG("deferred_close");
  
    tcp_poll (pcb, force_abort, 15); /* ~3sec from now */
    tcp_recv (pcb, handle_remote_close);
    tcp_sent (pcb, 0);
  }
  
  /* Convenience function to queue up a close-after-send.  */
  static err_t close_once_sent (void *arg, struct tcp_pcb *pcb, u16_t len)
  {
    ENDUSER_SETUP_DEBUG("close_once_sent");
  
    (void)arg; (void)len;
    deferred_close (pcb);
    return ERR_OK;
  }
  
  /* ------------------------------------------------------------------------- */
  
  /**
   * Get length of param value
   *
   * This is being called with a fragment of the parameters passed in the
   * URL for GET requests or part of the body of a POST request.
   * The string will look like one of these
   * "SecretPassword HTTP/1.1"
   * "SecretPassword&wifi_ssid=..."
   * "SecretPassword"
   * The string is searched for the first occurence of deliemiter '&' or ' '.
   * If found return the length up to that position.
   * If not found return the length of the string.
   *
   */
  static int enduser_setup_get_lenth_of_param_value(const char *str)
  {
    char *found = strpbrk (str, "& ");
    if (!found)
    {
      return strlen(str);
    }
    else
    {
      return found - str;
    }
  }
  
  /**
   * Load HTTP Payload
   *
   * @return - 0 if payload loaded successfully
   *           1 if default html was loaded
   *           2 if out of memory
   */
  static int enduser_setup_http_load_payload(void)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_http_load_payload");
  
    int err = VFS_RES_ERR;
    int err2 = VFS_RES_ERR;
    int file_len = 0;
  
    /* Try to open enduser_setup.html.gz from SPIFFS first */
    int f = vfs_open(http_html_gz_filename, "r");
  
    if (f)
    {
        err = vfs_lseek(f, 0, VFS_SEEK_END);
        file_len = (int) vfs_tell(f);
        err2 = vfs_lseek(f, 0, VFS_SEEK_SET);
    }
  
    if (!f || err == VFS_RES_ERR || err2 == VFS_RES_ERR)
    {
      if (f)
      {
        vfs_close(f);
      }
  
      /* If that didn't work, try to open enduser_setup.html from SPIFFS */
      f = vfs_open(http_html_filename, "r");
  
      if (f)
      {
          err = vfs_lseek(f, 0, VFS_SEEK_END);
          file_len = (int) vfs_tell(f);
          err2 = vfs_lseek(f, 0, VFS_SEEK_SET);
      }
    }
  
    char cl_hdr[30];
    size_t ce_len = 0;
  
    sprintf(cl_hdr, http_header_content_len_fmt, file_len);
    size_t cl_len = strlen(cl_hdr);
  
    if (!f || err == VFS_RES_ERR || err2 == VFS_RES_ERR)
    {
      ENDUSER_SETUP_DEBUG("Unable to load file enduser_setup.html, loading default HTML...");
  
      if (f)
      {
        vfs_close(f);
      }
  
      sprintf(cl_hdr, http_header_content_len_fmt, sizeof(enduser_setup_html_default));
      cl_len = strlen(cl_hdr);
      int html_len = LITLEN(enduser_setup_html_default);
  
      if (enduser_setup_html_default[0] == 0x1f && enduser_setup_html_default[1] == 0x8b)
      {
          ce_len = strlen(http_html_gzip_contentencoding);
          html_len = enduser_setup_html_default_len; /* Defined in enduser_setup/enduser_setup.html.gz.def.h by xxd -i */
          ENDUSER_SETUP_DEBUG("Content is gzipped");
      }
  
      int payload_len = LITLEN(http_header_200) + cl_len + ce_len + html_len;
      state->http_payload_len = payload_len;
      state->http_payload_data = (char *) malloc(payload_len);
  
      if (state->http_payload_data == NULL)
      {
        return 2;
      }
  
      int offset = 0;
      memcpy(&(state->http_payload_data[offset]), &(http_header_200), LITLEN(http_header_200));
      offset += LITLEN(http_header_200);
  
      if (ce_len > 0)
      {
          offset += sprintf(state->http_payload_data + offset, http_html_gzip_contentencoding, ce_len);
      }
  
      memcpy(&(state->http_payload_data[offset]), &(cl_hdr), cl_len);
      offset += cl_len;
      memcpy(&(state->http_payload_data[offset]), &(enduser_setup_html_default), sizeof(enduser_setup_html_default));
  
      return 1;
    }
  
    char magic[2];
    vfs_read(f, magic, 2);
  
    if (magic[0] == 0x1f && magic[1] == 0x8b)
    {
      ce_len = strlen(http_html_gzip_contentencoding);
      ENDUSER_SETUP_DEBUG("Content is gzipped");
    }
  
    int payload_len = LITLEN(http_header_200) + cl_len + ce_len + file_len;
    state->http_payload_len = payload_len;
    state->http_payload_data = (char *) malloc(payload_len);
  
    if (state->http_payload_data == NULL)
    {
      return 2;
    }
  
    vfs_lseek(f, 0, VFS_SEEK_SET);
  
    int offset = 0;
  
    memcpy(&(state->http_payload_data[offset]), &(http_header_200), LITLEN(http_header_200));
    offset += LITLEN(http_header_200);
  
    if (ce_len > 0)
    {
      offset += sprintf(state->http_payload_data + offset, http_html_gzip_contentencoding, ce_len);
    }
  
    memcpy(&(state->http_payload_data[offset]), &(cl_hdr), cl_len);
    offset += cl_len;
    vfs_read(f, &(state->http_payload_data[offset]), file_len);
    vfs_close(f);
  
    return 0;
  }
  
  
  /**
   * De-escape URL data
   *
   * Parse escaped and form encoded data of request.
   *
   * @return - return 0 if the HTTP parameter is decoded into a valid string.
   */
  static int enduser_setup_http_urldecode(char *dst, const char *src, int src_len, int dst_len)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_http_urldecode");
  
    char *dst_start = dst;
    char *dst_last = dst + dst_len - 1; /* -1 to reserve space for last \0 */
    char a, b;
    int i;
    for (i = 0; i < src_len && *src && dst < dst_last; ++i)
    {
      if ((*src == '%') && ((a = src[1]) && (b = src[2])) && (isxdigit(a) && isxdigit(b)))
      {
        if (a >= 'a')
        {
          a -= 'a'-'A';
        }
        if (a >= 'A')
        {
          a -= ('A' - 10);
        }
        else
        {
          a -= '0';
        }
        if (b >= 'a')
        {
          b -= 'a'-'A';
        }
        if (b >= 'A')
        {
          b -= ('A' - 10);
        }
        else
        {
          b -= '0';
        }
        *dst++ = 16 * a + b;
        src += 3;
        i += 2;
      } else {
        char c = *src++;
        if (c == '+')
        {
          c = ' ';
        }
        *dst++ = c;
      }
    }
    *dst++ = '\0';
    return (i < src_len); /* did we fail to process all the input? */
  }
  
  
  /**
   * Task to do the actual station configuration.
   * This config *cannot* be done in the network receive callback or serious
   * issues like memory corruption occur.
   */
  static void do_station_cfg (task_param_t param, uint8_t prio)
  {
    ENDUSER_SETUP_DEBUG("do_station_cfg");
  
    state->connecting = 1;
    struct station_config *cnf = (struct station_config *)param;
    (void)prio;
  
    /* Best-effort disconnect-reconfig-reconnect. If the device is currently
     * connected, the disconnect will work but the connect will report failure
     * (though it will actually start connecting). If the devices is not
     * connected, the disconnect may fail but the connect will succeed. A
     * solid head-in-the-sand approach seems to be the best tradeoff on
     * functionality-vs-code-size.
     * TODO: maybe use an error callback to at least report if the set config
     * call fails.
     */
    wifi_station_disconnect ();
    wifi_station_set_config (cnf);
    wifi_station_connect ();
    luaM_free(lua_getstate(), cnf);
  }
  
  /**
   * Count the number of occurences of a character in a string
   *
   * return the number of times the character was encountered in the string
   */
  static int count_char_occurence(const char *input, const char char_to_count) {
    const char *current = input;
    int occur = 0;
      while (*current != 0) {
          if (*current == char_to_count) occur++;
      current++;
    }
    return occur;
  }
  
  /* structure used to store the key/value pairs that we find in a HTTP POST body */
  struct keypairs_t {
    char **keypairs;
    int keypairs_nb;
  };
  
  static void enduser_setup_free_keypairs(struct keypairs_t *kp) {
      if (kp == NULL) return;
  
      if (kp->keypairs != NULL) {
          for (int i = 0; i < kp->keypairs_nb * 2; i++) {
        free(kp->keypairs[i]);
      }
    }
    free(kp->keypairs);
    free(kp);
  }
  
  static struct keypairs_t * enduser_setup_alloc_keypairs(int kp_number ){
      struct keypairs_t *kp = malloc(sizeof(struct keypairs_t));
      os_memset(kp, 0, sizeof(struct keypairs_t));
  
      kp->keypairs = malloc(kp_number * 2 * sizeof(char *));
      kp->keypairs_nb = kp_number;
      return kp;
  }
  
  /**
   * Parses a form-urlencoded body into a struct keypairs_t, which contains an array of key,values strings and the size of the array.
   */
  static struct keypairs_t *enduser_setup_get_keypairs_from_form(char *form_body, int form_length) {
    int keypair_nb = count_char_occurence(form_body, '&') + 1;
    int equal_nb = count_char_occurence(form_body, '=');
  
    if (keypair_nb == 1 && equal_nb == 0) {
      ENDUSER_SETUP_DEBUG("No keypair in form body");
      return NULL;
    }
  
    struct keypairs_t *kp = enduser_setup_alloc_keypairs(keypair_nb);
  
    int current_idx = 0;
    int err;
  
    char *body_copy = malloc(form_length+1);
    os_bzero(body_copy, form_length+1);
    os_memcpy(body_copy, form_body, form_length);
    char *tok = strtok(body_copy, "=");
  
    char last_tok = '=';
    while (tok) {
      size_t len = strlen(tok);
      kp->keypairs[current_idx] = malloc(len + 1);
      err = enduser_setup_http_urldecode(kp->keypairs[current_idx], tok, len, len + 1);
      if (err) {
        ENDUSER_SETUP_DEBUG("Unable to decode parameter");
        enduser_setup_free_keypairs(kp);
        free(body_copy);
        return NULL;
      }
  
      current_idx++;
      if (current_idx > keypair_nb*2) {
        ENDUSER_SETUP_DEBUG("Too many keypairs!");
        enduser_setup_free_keypairs(kp);
        free(body_copy);
        return NULL;
      }
  
      if (last_tok == '=') {
        tok = strtok(NULL, "&"); // now search for the '&'
        last_tok='&';
      } else {
        tok = strtok(NULL, "="); // search for the next '='
        last_tok='=';
      }
    }
    free(body_copy);
    return kp;
  }
  
  
  /**
   * This function saves the form data received when the configuration is sent to the ESP into a eus_params.lua file
   */
  static int enduser_setup_write_file_with_extra_configuration_data(char *form_body, int form_length) {
    ENDUSER_SETUP_DEBUG("enduser: write data from posted form");
    ENDUSER_SETUP_DEBUG(form_body);
  
    // We will save the form data into a file in the LUA format: KEY="VALUE", so that configuration data is available for load in the lua code.
    // As input, we have a string as such: "key1=value1&key2=value2&key3=value%203" (urlencoded), the number of '&' tells us how many keypairs there are (the count + 1)
  
    struct keypairs_t *kp = enduser_setup_get_keypairs_from_form(form_body, form_length);
    if (kp == NULL || kp->keypairs_nb == 0) {
      ENDUSER_SETUP_DEBUG("enduser: No extra configuration.");
      if (kp != NULL) enduser_setup_free_keypairs(kp);
      return 1;
    }
  
    // Now that we have the keys and the values, let's save them in a lua file
    int p_file = vfs_open("eus_params.lua", "w");
    if (p_file == 0)
    {
      ENDUSER_SETUP_DEBUG("Can't open file in write mode!");
      enduser_setup_free_keypairs(kp);
      return 1;
    }
  
    // write all key pairs as KEY="VALUE"\n into a Lua table, example:
    // local p = {}
    // p.wifi_ssid="ssid"
    // p.wifi_password="password"
    // p.device_name="foo-node"
    // return p
    vfs_write(p_file, "local p={}\n", 11);
    int idx = 0;
    for( idx = 0; idx < kp->keypairs_nb*2; idx=idx+2){
      char* to_write = kp->keypairs[idx];
      size_t length = strlen(to_write);
  
      vfs_write(p_file, "p.", 2);
  
      vfs_write(p_file, to_write, length);
  
      vfs_write(p_file, "=\"", 2);
  
      to_write = kp->keypairs[idx+1];
      length = strlen(to_write);
      vfs_write(p_file, to_write, length);
  
      vfs_write(p_file, "\"\n", 2);
    }
    vfs_write(p_file, "return p\n", 9);
  
    vfs_close(p_file);
    enduser_setup_free_keypairs(kp);
    // TODO: we could call back in the LUA with an associative table setup, but this is MVP2...
    return 0;
  }
  
  /**
   * Handle HTTP Credentials
   *
   * @return - return 0 if credentials are found and handled successfully
   *           return 1 if credentials aren't found
   *           return 2 if an error occured
   */
  static int enduser_setup_http_handle_credentials(char *data, unsigned short data_len)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_http_handle_credentials");
  
    state->success = 0;
    state->lastStationStatus = 0;
  
    char *name_str = strstr(data, "wifi_ssid=");
    char *pwd_str = strstr(data, "wifi_password=");
    if (name_str == NULL || pwd_str == NULL)
    {
      ENDUSER_SETUP_DEBUG("Password or SSID string not found");
      return 1;
    }
  
    int name_field_len = LITLEN("wifi_ssid=");
    int pwd_field_len = LITLEN("wifi_password=");
    char *name_str_start = name_str + name_field_len;
    char *pwd_str_start = pwd_str + pwd_field_len;
  
    int name_str_len = enduser_setup_get_lenth_of_param_value(name_str_start);
    int pwd_str_len = enduser_setup_get_lenth_of_param_value(pwd_str_start);
  
  
    struct station_config *cnf = luaM_malloc(lua_getstate(), sizeof(struct station_config));
    memset(cnf, 0, sizeof(struct station_config));
    cnf->threshold.rssi = -127;
    cnf->threshold.authmode = AUTH_OPEN;
  
    int err;
    err  = enduser_setup_http_urldecode(cnf->ssid, name_str_start, name_str_len, sizeof(cnf->ssid));
    err |= enduser_setup_http_urldecode(cnf->password, pwd_str_start, pwd_str_len, sizeof(cnf->password));
    if (err != 0 || strlen(cnf->ssid) == 0)
    {
      ENDUSER_SETUP_DEBUG("Unable to decode HTTP parameter to valid password or SSID");
      return 1;
    }
  
    ENDUSER_SETUP_DEBUG("");
    ENDUSER_SETUP_DEBUG("WiFi Credentials Stored");
    ENDUSER_SETUP_DEBUG("-----------------------");
    ENDUSER_SETUP_DEBUG("name: ");
    ENDUSER_SETUP_DEBUG(cnf->ssid);
    ENDUSER_SETUP_DEBUG("pass: ");
    ENDUSER_SETUP_DEBUG(cnf->password);
    ENDUSER_SETUP_DEBUG("-----------------------");
    ENDUSER_SETUP_DEBUG("");
  
    task_post_medium(do_station_cfg_handle, (task_param_t) cnf);
  
    return 0;
  }
  
  
  /**
   * Serve HTML
   *
   * @return - return 0 if html was served successfully
   */
  static int enduser_setup_http_serve_header(struct tcp_pcb *http_client, const char *header, uint32_t header_len)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_http_serve_header");
  
    err_t err = tcp_write (http_client, header, header_len, TCP_WRITE_FLAG_COPY);
    if (err != ERR_OK)
    {
      deferred_close (http_client);
      ENDUSER_SETUP_ERROR("http_serve_header failed on tcp_write", ENDUSER_SETUP_ERR_UNKOWN_ERROR, ENDUSER_SETUP_ERR_NONFATAL);
    }
  
    return 0;
  }
  
  
  static err_t streamout_sent (void *arg, struct tcp_pcb *pcb, u16_t len)
  {
    ENDUSER_SETUP_DEBUG("streamout_sent");
  
    (void)len;
    unsigned offs = (unsigned)arg;
  
    if (!state || !state->http_payload_data)
    {
      tcp_abort (pcb);
      return ERR_ABRT;
    }
  
    unsigned wanted_len = state->http_payload_len - offs;
    unsigned buf_free = tcp_sndbuf (pcb);
    if (buf_free < wanted_len)
      wanted_len = buf_free;
  
    /* no-copy write */
    err_t err = tcp_write (pcb, state->http_payload_data + offs, wanted_len, 0);
    if (err != ERR_OK)
    {
      ENDUSER_SETUP_DEBUG("streaming out html failed");
      tcp_abort (pcb);
      return ERR_ABRT;
    }
  
    offs += wanted_len;
  
    if (offs >= state->http_payload_len)
    {
      tcp_sent (pcb, 0);
      deferred_close (pcb);
      free(state->http_payload_data);
      state->http_payload_data = NULL;
    }
    else
      tcp_arg (pcb, (void *)offs);
  
    return ERR_OK;
  }
  
  
  /**
   * Serve HTML
   *
   * @return - return 0 if html was served successfully
   */
  static int enduser_setup_http_serve_html(struct tcp_pcb *http_client)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_http_serve_html");
  
    if (state->http_payload_data == NULL)
    {
      enduser_setup_http_load_payload();
    }
  
    unsigned chunklen = tcp_sndbuf (http_client);
    tcp_arg (http_client, (void *)chunklen);
    tcp_recv (http_client, 0); /* avoid confusion about the tcp_arg */
    tcp_sent (http_client, streamout_sent);
    /* Begin the no-copy stream-out here */
    err_t err = tcp_write (http_client, state->http_payload_data, chunklen, 0);
    if (err != 0)
    {
      ENDUSER_SETUP_ERROR("http_serve_html failed. tcp_write failed", ENDUSER_SETUP_ERR_UNKOWN_ERROR, ENDUSER_SETUP_ERR_NONFATAL);
    }
  
    return 0;
  }
  
  
  static void enduser_setup_serve_status(struct tcp_pcb *conn)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_serve_status");
  
    const char fmt[] =
      "HTTP/1.1 200 OK\r\n"
      "Cache-control:no-cache\r\n"
      "Connection:close\r\n"
      "Access-Control-Allow-Origin: *\r\n"
      "Content-type:text/plain\r\n"
      "Content-length: %d\r\n"
      "\r\n"
      "%s";
    const char *states[] =
    {
      "Idle.",
      "Connecting to \"%s\".",
      "Failed to connect to \"%s\" - Wrong password.",
      "Failed to connect to \"%s\" - Network not found.",
      "Failed to connect.",
      "Connected to \"%s\" (%s)."
    };
  
    const size_t num_states = sizeof(states)/sizeof(states[0]);
    uint8_t curr_state = state->lastStationStatus > 0 ? state->lastStationStatus : wifi_station_get_connect_status ();
    if (curr_state < num_states)
    {
      switch (curr_state)
      {
        case STATION_CONNECTING:
        case STATION_WRONG_PASSWORD:
        case STATION_NO_AP_FOUND:
        case STATION_GOT_IP:
        {
          const char *s = states[curr_state];
          struct station_config config;
          wifi_station_get_config(&config);
          config.ssid[31] = '\0';
  
          struct ip_info ip_info;
  
          wifi_get_ip_info(STATION_IF , &ip_info);
  
          char ip_addr[16];
          ip_addr[0] = '\0';
          if (curr_state == STATION_GOT_IP)
          {
            sprintf (ip_addr, "%d.%d.%d.%d", IP2STR(&ip_info.ip.addr));
          }
  
          int state_len = strlen(s);
          int ip_len = strlen(ip_addr);
          int ssid_len = strlen(config.ssid);
          int status_len = state_len + ssid_len + ip_len + 1;
          char status_buf[status_len];
          memset(status_buf, 0, status_len);
          status_len = sprintf(status_buf, s, config.ssid, ip_addr);
  
          int buf_len = sizeof(fmt) + status_len + 10; /* 10 = (9+1), 1 byte is '\0' and 9 are reserved for length field */
          char buf[buf_len];
          memset(buf, 0, buf_len);
          int output_len = sprintf(buf, fmt, status_len, status_buf);
  
          enduser_setup_http_serve_header(conn, buf, output_len);
        }
        break;
  
        /* Handle non-formatted strings */
        default:
        {
          const char *s = states[curr_state];
          int status_len = strlen(s);
          int buf_len = sizeof(fmt) + status_len + 10; /* 10 = (9+1), 1 byte is '\0' and 9 are reserved for length field */
          char buf[buf_len];
          memset(buf, 0, buf_len);
          int output_len = sprintf(buf, fmt, status_len, s);
  
          enduser_setup_http_serve_header(conn, buf, output_len);
        }
        break;
      }
    }
    else
    {
      enduser_setup_http_serve_header(conn, http_header_500, LITLEN(http_header_500));
    }
  }
  
  static void enduser_setup_serve_status_as_json (struct tcp_pcb *http_client)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_serve_status_as_json");
  
    /* If the station is currently shut down because of wi-fi channel issue, use the cached status */
    uint8_t curr_status = state->lastStationStatus > 0 ? state->lastStationStatus : wifi_station_get_connect_status ();
  
    char json_payload[64];
  
    struct ip_info ip_info;
  
    if (curr_status == 5)
    {
      wifi_get_ip_info(STATION_IF , &ip_info);
      /* If IP address not yet available, get now */
      if (strlen(ipaddr) == 0)
      {
        sprintf(ipaddr, "%d.%d.%d.%d", IP2STR(&ip_info.ip.addr));
      }
      sprintf(json_payload, "{\"deviceid\":\"%s\", \"status\":%d}", ipaddr, curr_status);
    }
    else
    {
      sprintf(json_payload, "{\"deviceid\":\"%06X\", \"status\":%d}", system_get_chip_id(), curr_status);
    }
  
    const char fmt[] =
      "HTTP/1.1 200 OK\r\n"
      "Cache-Control: no-cache\r\n"
      "Connection: close\r\n"
      "Access-Control-Allow-Origin: *\r\n"
      "Content-Type: application/json\r\n"
      "Content-Length: %d\r\n"
      "\r\n"
      "%s";
  
    int len = strlen(json_payload);
    char buf[strlen(fmt) + NUMLEN(len) + len - 4];
    len = sprintf (buf, fmt, len, json_payload);
    enduser_setup_http_serve_header (http_client, buf, len);
  }
  
  
  static void enduser_setup_handle_OPTIONS (struct tcp_pcb *http_client, char *data, unsigned short data_len)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_handle_OPTIONS");
  
    const char json[] =
      "HTTP/1.1 200 OK\r\n"
      "Cache-Control: no-cache\r\n"
      "Connection: close\r\n"
      "Content-Type: application/json\r\n"
      "Content-Length: 0\r\n"
      "Access-Control-Allow-Origin: *\r\n"
      "Access-Control-Allow-Methods: GET\r\n"
      "Access-Control-Allow-Age: 300\r\n"
      "\r\n";
  
    const char others[] =
      "HTTP/1.1 200 OK\r\n"
      "Cache-Control: no-cache\r\n"
      "Connection: close\r\n"
      "Content-Length: 0\r\n"
      "\r\n";
  
    int type = 0;
  
    if (strncmp(data, "OPTIONS ", 8) == 0)
    {
      if (strncmp(data + 8, "/aplist", 7) == 0 || strncmp(data + 8, "/setwifi?", 9) == 0 || strncmp(data + 8, "/status.json", 12) == 0)
      {
        enduser_setup_http_serve_header (http_client, json, strlen(json));
        return;
     }
    }
    enduser_setup_http_serve_header (http_client, others, strlen(others));
    return;
  }
  
  
  static void enduser_setup_handle_POST(struct tcp_pcb *http_client, char* data, size_t data_len)
  {
      ENDUSER_SETUP_DEBUG("Handling POST");
      if (strncmp(data + 5, "/setwifi ", 9) == 0) // User clicked the submit button
      {
        char* body=strstr(data, "\r\n\r\n");
        if( body == NULL)
        {
          enduser_setup_http_serve_header(http_client, http_header_400, LITLEN(http_header_400));
          return;
        }
        body += 4; // length of the double CRLF found above
        int bodylength = (data + data_len) - body;
        switch (enduser_setup_http_handle_credentials(body, bodylength))
        {
          case 0: {
            // all went fine, extract all the form data into a file
            enduser_setup_write_file_with_extra_configuration_data(body, bodylength);
            // redirect user to the base page with the trying flag
            enduser_setup_http_serve_header(http_client, http_header_302_trying, LITLEN(http_header_302_trying));
            break;
          }
          case 1:
            enduser_setup_http_serve_header(http_client, http_header_400, LITLEN(http_header_400));
            break;
          default:
            ENDUSER_SETUP_ERROR_VOID("http_recvcb failed. Failed to handle wifi credentials.", ENDUSER_SETUP_ERR_UNKOWN_ERROR, ENDUSER_SETUP_ERR_NONFATAL);
            break;
        }
      } else {
        enduser_setup_http_serve_header(http_client, http_header_404, LITLEN(http_header_404));
      }
  }
  
  
  /* --- WiFi AP scanning support -------------------------------------------- */
  
  static void free_scan_listeners (void)
  {
    ENDUSER_SETUP_DEBUG("free_scan_listeners");
  
    if (!state || !state->scan_listeners)
    {
      return;
    }
  
    scan_listener_t *l = state->scan_listeners , *next = 0;
    while (l)
    {
      next = l->next;
      free (l);
      l = next;
    }
    state->scan_listeners = 0;
  }
  
  
  static void remove_scan_listener (scan_listener_t *l)
  {
    ENDUSER_SETUP_DEBUG("remove_scan_listener");
  
    if (state)
    {
      scan_listener_t **sl = &state->scan_listeners;
      while (*sl)
      {
        /* Remove any and all references to the closed conn from the scan list */
        if (*sl == l)
        {
          *sl = l->next;
          free (l);
          /* No early exit to guard against multi-entry on list */
        }
        else
          sl = &(*sl)->next;
      }
    }
  }
  
  
  static char *escape_ssid (char *dst, const char *src)
  {
    for (int i = 0; i < 32 && src[i]; ++i)
    {
      if (src[i] == '\\' || src[i] == '"')
      {
        *dst++ = '\\';
      }
      *dst++ = src[i];
    }
    return dst;
  }
  
  
  static void notify_scan_listeners (const char *payload, size_t sz)
  {
    ENDUSER_SETUP_DEBUG("notify_scan_listeners");
  
    if (!state)
    {
      return;
    }
  
    for (scan_listener_t *l = state->scan_listeners; l; l = l->next)
    {
      if (tcp_write (l->conn, payload, sz, TCP_WRITE_FLAG_COPY) != ERR_OK)
      {
        ENDUSER_SETUP_DEBUG("failed to send wifi list");
        tcp_abort (l->conn);
      }
      else
        tcp_sent (l->conn, close_once_sent); /* TODO: time-out sends? */
      l->conn = 0;
    }
  
    free_scan_listeners ();
  }
  
  
  static void on_scan_done (void *arg, STATUS status)
  {
    ENDUSER_SETUP_DEBUG("on_scan_done");
  
    if (!state || !state->scan_listeners)
    {
      return;
    }
  
    if (status == OK)
    {
      unsigned num_nets = 0;
      for (struct bss_info *wn = arg; wn; wn = wn->next.stqe_next)
      {
        ++num_nets;
      }
  
      const char header_fmt[] =
        "HTTP/1.1 200 OK\r\n"
        "Connection:close\r\n"
        "Cache-control:no-cache\r\n"
        "Access-Control-Allow-Origin: *\r\n"
        "Content-type:application/json\r\n"
        "Content-length:%4d\r\n"
        "\r\n";
      const size_t hdr_sz = sizeof (header_fmt) +1 -1; /* +expand %4d, -\0 */
  
      /* To be able to safely escape a pathological SSID, we need 2*32 bytes */
      const size_t max_entry_sz = 35 + 2*32 + 9; /* {"ssid":"","rssi":,"chan":,"auth":} */
      const size_t alloc_sz = hdr_sz + num_nets * max_entry_sz + 3;
      char *http = calloc (1, alloc_sz);
      if (!http)
      {
        goto serve_500;
      }
  
      char *p = http + hdr_sz; /* start body where we know it will be */
      /* p[0] will be clobbered when we print the header, so fill it in last */
      ++p;
      for (struct bss_info *wn = arg; wn; wn = wn->next.stqe_next)
      {
        if (wn != arg)
        {
          *p++ = ',';
        }
  
        const char entry_start[] = "{\"ssid\":\"";
        strcpy (p, entry_start);
        p += sizeof (entry_start) -1;
  
        p = escape_ssid (p, wn->ssid);
  
        const char entry_mid[] = "\",\"rssi\":";
        strcpy (p, entry_mid);
        p += sizeof (entry_mid) -1;
  
        p += sprintf (p, "%d", wn->rssi);
  
        const char entry_chan[] = ",\"chan\":";
        strcpy (p, entry_chan);
        p += sizeof (entry_chan) -1;
  
        p += sprintf (p, "%d", wn->channel);
  
        const char entry_auth[] = ",\"auth\":";
        strcpy (p, entry_auth);
        p += sizeof (entry_auth) -1;
  
        p += sprintf (p, "%d", wn->authmode);
  
        *p++ = '}';
      }
      *p++ = ']';
  
      size_t body_sz = (p - http) - hdr_sz;
      sprintf (http, header_fmt, body_sz);
      http[hdr_sz] = '['; /* Rewrite the \0 with the correct start of body */
  
      notify_scan_listeners (http, hdr_sz + body_sz);
      ENDUSER_SETUP_DEBUG(http + hdr_sz);
  
      free (http);
      return;
    }
  
  serve_500:
    notify_scan_listeners (http_header_500, LITLEN(http_header_500));
  }
  
  /* ---- end WiFi AP scan support ------------------------------------------- */
  
  static err_t enduser_setup_http_recvcb(void *arg, struct tcp_pcb *http_client, struct pbuf *p, err_t err)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_http_recvcb");
  
    if (!state || err != ERR_OK)
    {
      if (!state)
        ENDUSER_SETUP_DEBUG("ignoring received data while stopped");
      tcp_abort (http_client);
      return ERR_ABRT;
    }
  
    tcp_arg_t *tcp_arg_ptr = arg;
  
    if (!p) /* remote side closed, close our end too */
    {
      ENDUSER_SETUP_DEBUG("connection closed");
      if (tcp_arg_ptr) {
        if (tcp_arg_ptr->struct_type == SCAN_LISTENER_STRUCT_TYPE) {
          remove_scan_listener ((scan_listener_t *)tcp_arg_ptr);
        } else if (tcp_arg_ptr->struct_type == HTTP_REQUEST_BUFFER_STRUCT_TYPE) {
          free(tcp_arg_ptr);
        }
      }
  
      deferred_close (http_client);
      return ERR_OK;
    }
  
    http_request_buffer_t *hrb;
    if (!tcp_arg_ptr) {
      hrb = calloc(1, sizeof(*hrb));
      if (!hrb) {
        goto general_fail;
      }
      hrb->struct_type = HTTP_REQUEST_BUFFER_STRUCT_TYPE;
      tcp_arg(http_client, hrb);
    } else if (tcp_arg_ptr->struct_type == HTTP_REQUEST_BUFFER_STRUCT_TYPE) {
      hrb = (http_request_buffer_t *) tcp_arg_ptr;
    } else {
      goto general_fail;
    }
  
    // Append the new data
    size_t newlen = hrb->length + p->tot_len;
    void *old_hrb = hrb;
    hrb = realloc(hrb, sizeof(*hrb) + newlen + 1);
    tcp_arg(http_client, hrb);
    if (!hrb) {
      free(old_hrb);
      goto general_fail;
    }
  
    pbuf_copy_partial(p, hrb->data + hrb->length, p->tot_len, 0);
    hrb->data[newlen] = 0;
    hrb->length = newlen;
  
    tcp_recved (http_client, p->tot_len);
    pbuf_free (p);
  
    // see if we have the whole request.
    // Rely on the fact that the header should not contain a null character
    char *end_of_header = strstr(hrb->data, "\r\n\r\n");
    if (end_of_header == 0) {
      return ERR_OK;
    }
  
    end_of_header += 4;
  
    // We have the entire header, now see if there is any content. If we don't find the
    // content-length header, then there is no content and we can process immediately.
    // The content-length header can also be missing if the browser is using chunked
    // encoding.
  
    bool is_chunked = FALSE;
    for (const char *hdr = hrb->data; hdr && hdr < end_of_header; hdr = strchr(hdr, '\n')) {
      hdr += 1; // Skip the \n
      if (strncasecmp(hdr, "transfer-encoding:", 18) == 0) {
        const char *field = hdr + 18;
  
        while (*field != '\n') {
          if (memcmp(field, "chunked", 7) == 0) {
            is_chunked = TRUE;
            break;
          }
          field++;
        }
      }
      if (strncasecmp(hdr, "Content-length:", 15) == 0) {
        // There is a content-length header
        const char *field = hdr + 15;
        size_t extra = strtol(field + 1, 0, 10);
        if (extra + (end_of_header - hrb->data) > hrb->length) {
          return ERR_OK;
        }
      }
    }
  
    if (is_chunked) {
      // More complex to determine if the whole body has arrived
      // Format is one or more chunks each preceded by their length (in hex)
      // A zero length chunk ends the body
      const char *ptr = end_of_header;
      bool seen_end = FALSE;
  
      while (ptr < hrb->data + hrb->length && ptr > hrb->data) {
        size_t chunk_len = strtol(ptr, 0, 16);
        // Skip to end of chunk length (note that there can be parameters after the length)
        ptr = strchr(ptr, '\n');
        if (!ptr) {
          // Don't have the entire chunk header
          return ERR_OK;
        }
        ptr++;
        ptr += chunk_len;
        if (chunk_len == 0) {
          seen_end = TRUE;
          break;
        }
        if (ptr + 2 > hrb->data + hrb->length) {
          // We don't have the CRLF yet
          return ERR_OK;
        }
        if (memcmp(ptr, "\r\n", 2)) {
          // Bail out here -- something bad happened
          goto general_fail;
        }
        ptr += 2;
      }
      if (!seen_end) {
        // Still waiting for the end chunk
        return ERR_OK;
      }
  
      // Now rewrite the buffer to eliminate all the chunk headers
      const char *src = end_of_header;
      char *dst = end_of_header;
  
      while (src < hrb->data + hrb->length && src > hrb->data) {
        size_t chunk_len = strtol(src, 0, 16);
        src = strchr(src, '\n');
        src++;
        if (chunk_len == 0) {
          break;
        }
        memmove(dst, src, chunk_len);
        dst += chunk_len;
        src += chunk_len + 2;
      }
      *dst = '\0';    // Move the null termination down
      hrb->length = dst - hrb->data;  // Adjust the length down
    }
  
    err_t ret = ERR_OK;
  
    char *data = hrb->data;
    size_t data_len = hrb->length;
  
    tcp_arg(http_client, 0);    // Forget the data pointer.
  
  #if ENDUSER_SETUP_DEBUG_SHOW_HTTP_REQUEST
    ENDUSER_SETUP_DEBUG(data);
  #endif
  
    if (strncmp(data, "GET ", 4) == 0)
    {
      if (strncmp(data + 4, "/ ", 2) == 0 || strncmp(data + 4, "/?", 2) == 0)
      {
        if (enduser_setup_http_serve_html(http_client) != 0)
        {
          goto general_fail;
        }
        else
        {
          goto free_out; /* streaming now in progress */
        }
      }
      else if (strncmp(data + 4, "/aplist", 7) == 0)
      {
        /* Don't do an AP Scan while station is trying to connect to Wi-Fi */
        if (state->connecting == 0)
        {
          scan_listener_t *sl = malloc (sizeof (scan_listener_t));
          if (!sl)
          {
            ENDUSER_SETUP_ERROR("out of memory", ENDUSER_SETUP_ERR_OUT_OF_MEMORY, ENDUSER_SETUP_ERR_NONFATAL);
          }
  
          sl->struct_type = SCAN_LISTENER_STRUCT_TYPE;
  
          bool already = (state->scan_listeners != NULL);
  
          tcp_arg (http_client, sl);
          /* TODO: check if also need a tcp_err() cb, or if recv() is enough */
          sl->conn = http_client;
          sl->next = state->scan_listeners;
          state->scan_listeners = sl;
  
          if (!already)
          {
            if (!wifi_station_scan(NULL, on_scan_done))
            {
              enduser_setup_http_serve_header(http_client, http_header_500, LITLEN(http_header_500));
              deferred_close (sl->conn);
              sl->conn = 0;
              free_scan_listeners();
            }
          }
          goto free_out; /* request queued */
        }
        else
        {
          /* Return No Content status to the caller */
          enduser_setup_http_serve_header(http_client, http_header_204, LITLEN(http_header_204));
        }
      }
      else if (strncmp(data + 4, "/status.json", 12) == 0)
      {
        enduser_setup_serve_status_as_json(http_client);
      }
      else if (strncmp(data + 4, "/status", 7) == 0)
      {
        enduser_setup_serve_status(http_client);
      }
      else if (strncmp(data + 4, "/update?", 8) == 0)
      {
        switch (enduser_setup_http_handle_credentials(data, data_len))
        {
          case 0:
            enduser_setup_http_serve_header(http_client, http_header_302, LITLEN(http_header_302));
            break;
          case 1:
            enduser_setup_http_serve_header(http_client, http_header_400, LITLEN(http_header_400));
            break;
          default:
            ENDUSER_SETUP_ERROR("http_recvcb failed. Failed to handle wifi credentials.", ENDUSER_SETUP_ERR_UNKOWN_ERROR, ENDUSER_SETUP_ERR_NONFATAL);
            break;
        }
      }
      else
      {
        // All other URLs redirect to http://nodemcu.portal/ -- this triggers captive portal.
        enduser_setup_http_serve_header(http_client, http_header_302, LITLEN(http_header_302));
      }
    }
    else if (strncmp(data, "OPTIONS ", 8) == 0)
    {
       enduser_setup_handle_OPTIONS(http_client, data, data_len);
    }
    else if (strncmp(data, "POST ", 5) == 0)
    {
      enduser_setup_handle_POST(http_client, data, data_len);
    }
    else /* not GET or OPTIONS */
    {
      enduser_setup_http_serve_header(http_client, http_header_405, LITLEN(http_header_405));
    }
  
    deferred_close (http_client);
  
  free_out:
    free (hrb);
    return ret;
  
  general_fail:
    ENDUSER_SETUP_ERROR("http_recvcb failed. Unable to send HTML.", ENDUSER_SETUP_ERR_UNKOWN_ERROR, ENDUSER_SETUP_ERR_NONFATAL);
  }
  
  
  static err_t enduser_setup_http_connectcb(void *arg, struct tcp_pcb *pcb, err_t err)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_http_connectcb");
  
    if (!state)
    {
      ENDUSER_SETUP_DEBUG("connect callback but no state?!");
      tcp_abort (pcb);
      return ERR_ABRT;
    }
  
    tcp_accepted (state->http_pcb);
    tcp_arg(pcb, 0);              // Initialize to known value
    tcp_recv (pcb, enduser_setup_http_recvcb);
    tcp_nagle_disable (pcb);
    return ERR_OK;
  }
  
  
  static int enduser_setup_http_start(void)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_http_start");
    struct tcp_pcb *pcb = tcp_new ();
    if (pcb == NULL)
    {
      ENDUSER_SETUP_ERROR("http_start failed. Memory allocation failed (http_pcb == NULL).", ENDUSER_SETUP_ERR_OUT_OF_MEMORY, ENDUSER_SETUP_ERR_FATAL);
    }
  
    if (tcp_bind (pcb, IP_ADDR_ANY, 80) != ERR_OK)
    {
      ENDUSER_SETUP_ERROR("http_start bind failed", ENDUSER_SETUP_ERR_SOCKET_ALREADY_OPEN, ENDUSER_SETUP_ERR_FATAL);
    }
  
    state->http_pcb = tcp_listen (pcb);
    if (!state->http_pcb)
    {
      tcp_abort(pcb); /* original wasn't freed for us */
      ENDUSER_SETUP_ERROR("http_start listen failed", ENDUSER_SETUP_ERR_SOCKET_ALREADY_OPEN, ENDUSER_SETUP_ERR_FATAL);
    }
  
    tcp_accept (state->http_pcb, enduser_setup_http_connectcb);
  
    /* TODO: check lwip tcp timeouts */
  #if 0
    err = espconn_regist_time(state->espconn_http_tcp, 2, 0);
    if (err == ESPCONN_ARG)
    {
      ENDUSER_SETUP_ERROR("http_start failed. Unable to set TCP timeout.", ENDUSER_SETUP_ERR_CONNECTION_NOT_FOUND, ENDUSER_SETUP_ERR_NONFATAL | ENDUSER_SETUP_ERR_NO_RETURN);
    }
  #endif
  
    int err = enduser_setup_http_load_payload();
    if (err == 1)
    {
      ENDUSER_SETUP_DEBUG("enduser_setup_http_start info. Loaded default HTML.");
    }
    else if (err == 2)
    {
      ENDUSER_SETUP_ERROR("http_start failed. Unable to allocate memory for HTTP payload.", ENDUSER_SETUP_ERR_OUT_OF_MEMORY, ENDUSER_SETUP_ERR_FATAL);
    }
  
    return 0;
  }
  
  
  static void enduser_setup_http_stop(void)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_http_stop");
  
    if (state && state->http_pcb)
    {
      tcp_close (state->http_pcb); /* cannot fail for listening sockets */
      state->http_pcb = 0;
    }
  }
  
  static void enduser_setup_ap_stop(void)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_ap_stop");
  
    wifi_set_opmode(~SOFTAP_MODE & wifi_get_opmode());
  }
  
  
  static void enduser_setup_ap_start(void)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_ap_start");
  
    struct softap_config cnf;
    memset(&(cnf), 0, sizeof(struct softap_config));
  
  #ifndef ENDUSER_SETUP_AP_SSID
    #define ENDUSER_SETUP_AP_SSID "NodeMCU"
  #endif
  
    if (state->ap_ssid) {
      strncpy(cnf.ssid, state->ap_ssid, sizeof(cnf.ssid));
      cnf.ssid_len = strlen(cnf.ssid);
    } else {
      char ssid[] = ENDUSER_SETUP_AP_SSID;
      int ssid_name_len = strlen(ssid);
      memcpy(&(cnf.ssid), ssid, ssid_name_len);
  
      uint8_t mac[6];
      wifi_get_macaddr(SOFTAP_IF, mac);
      cnf.ssid[ssid_name_len] = '_';
      sprintf(cnf.ssid + ssid_name_len + 1, "%02X%02X%02X", mac[3], mac[4], mac[5]);
      cnf.ssid_len = ssid_name_len + 7;
    }
    cnf.channel = state == NULL? 1 : state->softAPchannel;
    cnf.authmode = AUTH_OPEN;
    cnf.ssid_hidden = 0;
    cnf.max_connection = 5;
    cnf.beacon_interval = 100;
    wifi_set_opmode(STATIONAP_MODE);
    wifi_softap_set_config(&cnf);
  
  #if ENDUSER_SETUP_DEBUG_ENABLE
    char debuginfo[100];
    sprintf(debuginfo, "SSID: %s, CHAN: %d", cnf.ssid, cnf.channel);
    ENDUSER_SETUP_DEBUG(debuginfo);
  #endif
  }
  
  static void on_initial_scan_done (void *arg, STATUS status)
  {
    ENDUSER_SETUP_DEBUG("on_initial_scan_done");
  
    if (state == NULL)
    {
      return;
    }
  
    int8_t rssi = -100;
  
    if (status == OK)
    {
      /* Find the strongest signal and use the same wi-fi channel for the SoftAP. This is based on an assumption that end-user
       * will likely be choosing that AP to connect to. Since ESP only has one radio, STA and AP must share same channel. This
       * algorithm tries to minimize the SoftAP unavailability when the STA is connecting to verify. If the STA must switch to
       * another wi-fi channel, then the SoftAP will follow it, but the end-user's device will not know that the SoftAP is no
       * longer there until it times out. To mitigate, we try to prevent the need to switch channels, and if a switch does occur,
       * be quick about returning to this channel so that status info can be delivered to the end-user's device before shutting
       * down EUS.
       */
      for (struct bss_info *wn = arg; wn; wn = wn->next.stqe_next)
      {
        if (wn->rssi > rssi)
        {
          state->softAPchannel = wn->channel;
          rssi = wn->rssi;
        }
      }
    }
  
    enduser_setup_ap_start();
    enduser_setup_check_station_start();
  }
  
  static void enduser_setup_dns_recv_callback(void *arg, char *recv_data, unsigned short recv_len)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_dns_recv_callback.");
  
    struct espconn *callback_espconn = arg;
    struct ip_info ip_info;
  
    uint32_t qname_len = strlen(&(recv_data[12])) + 1; /* \0=1byte */
    uint32_t dns_reply_static_len = (uint32_t) sizeof(dns_header) + (uint32_t) sizeof(dns_body) + 2 + 4; /* dns_id=2bytes, ip=4bytes */
    uint32_t dns_reply_len = dns_reply_static_len + qname_len;
  
  #if ENDUSER_SETUP_DEBUG_ENABLE
    char *qname = malloc(qname_len + 12);
    if (qname != NULL)
    {
      sprintf(qname, "DNS QUERY = %s", &(recv_data[12]));
  
      uint32_t p;
      int i, j;
  
      for(i=12;i<(int)strlen(qname);i++)
      {
        p=qname[i];
        for(j=0;j<(int)p;j++)
        {
          qname[i]=qname[i+1];
          i=i+1;
        }
        qname[i]='.';
      }
      qname[i-1]='\0';
      ENDUSER_SETUP_DEBUG(qname);
      free(qname);
    }
  #endif
  
    uint8_t if_mode = wifi_get_opmode();
    if ((if_mode & SOFTAP_MODE) == 0)
    {
      ENDUSER_SETUP_ERROR_VOID("dns_recv_callback failed. Interface mode not supported.", ENDUSER_SETUP_ERR_UNKOWN_ERROR, ENDUSER_SETUP_ERR_FATAL);
    }
  
    uint8_t if_index = (if_mode == STATION_MODE? STATION_IF : SOFTAP_IF);
    if (wifi_get_ip_info(if_index , &ip_info) == false)
    {
      ENDUSER_SETUP_ERROR_VOID("dns_recv_callback failed. Unable to get interface IP.", ENDUSER_SETUP_ERR_UNKOWN_ERROR, ENDUSER_SETUP_ERR_FATAL);
    }
  
  
    char *dns_reply = (char *) malloc(dns_reply_len);
    if (dns_reply == NULL)
    {
      ENDUSER_SETUP_ERROR_VOID("dns_recv_callback failed. Failed to allocate memory.", ENDUSER_SETUP_ERR_OUT_OF_MEMORY, ENDUSER_SETUP_ERR_NONFATAL);
    }
  
    uint32_t insert_byte = 0;
    memcpy(&(dns_reply[insert_byte]), recv_data, 2);
    insert_byte += 2;
    memcpy(&(dns_reply[insert_byte]), dns_header, sizeof(dns_header));
    insert_byte += (uint32_t) sizeof(dns_header);
    memcpy(&(dns_reply[insert_byte]), &(recv_data[12]), qname_len);
    insert_byte += qname_len;
    memcpy(&(dns_reply[insert_byte]), dns_body, sizeof(dns_body));
    insert_byte += (uint32_t) sizeof(dns_body);
    memcpy(&(dns_reply[insert_byte]), &(ip_info.ip), 4);
  
    /* SDK 1.4.0 changed behaviour, for UDP server need to look up remote ip/port */
    remot_info *pr = 0;
    if (espconn_get_connection_info(callback_espconn, &pr, 0) != ESPCONN_OK)
    {
      ENDUSER_SETUP_ERROR_VOID("dns_recv_callback failed. Unable to get IP of UDP sender.", ENDUSER_SETUP_ERR_CONNECTION_NOT_FOUND, ENDUSER_SETUP_ERR_FATAL);
    }
    callback_espconn->proto.udp->remote_port = pr->remote_port;
    os_memmove(callback_espconn->proto.udp->remote_ip, pr->remote_ip, 4);
  
    int8_t err;
    err = espconn_send(callback_espconn, dns_reply, dns_reply_len);
    free(dns_reply);
    if (err == ESPCONN_MEM)
    {
      ENDUSER_SETUP_ERROR_VOID("dns_recv_callback failed. Failed to allocate memory for send.", ENDUSER_SETUP_ERR_OUT_OF_MEMORY, ENDUSER_SETUP_ERR_FATAL);
    }
    else if (err == ESPCONN_ARG)
    {
      ENDUSER_SETUP_ERROR_VOID("dns_recv_callback failed. Can't execute transmission.", ENDUSER_SETUP_ERR_CONNECTION_NOT_FOUND, ENDUSER_SETUP_ERR_FATAL);
    }
    else if (err == ESPCONN_MAXNUM)
    {
      ENDUSER_SETUP_ERROR_VOID("dns_recv_callback failed. Buffer full. Discarding...", ENDUSER_SETUP_ERR_MAX_NUMBER, ENDUSER_SETUP_ERR_NONFATAL);
    }
    else if (err == ESPCONN_IF)
    {
      ENDUSER_SETUP_ERROR_VOID("dns_recv_callback failed. Send UDP data failed", ENDUSER_SETUP_ERR_UNKOWN_ERROR, ENDUSER_SETUP_ERR_NONFATAL);
    }
    else if (err != 0)
    {
      ENDUSER_SETUP_ERROR_VOID("dns_recv_callback failed. espconn_send failed", ENDUSER_SETUP_ERR_UNKOWN_ERROR, ENDUSER_SETUP_ERR_FATAL);
    }
  }
  
  
  static void enduser_setup_free(void)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_free");
  
    if (state == NULL)
    {
      return;
    }
  
    /* Make sure no running timers are left. */
    os_timer_disarm(&(state->check_station_timer));
    os_timer_disarm(&(state->shutdown_timer));
  
    if (state->espconn_dns_udp != NULL)
    {
      if (state->espconn_dns_udp->proto.udp != NULL)
      {
        free(state->espconn_dns_udp->proto.udp);
      }
      free(state->espconn_dns_udp);
    }
  
    free(state->http_payload_data);
  
    free_scan_listeners ();
  
    free(state->ap_ssid);
  
    free(state);
    state = NULL;
  }
  
  
  static int enduser_setup_dns_start(void)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_dns_start");
  
    if (state->espconn_dns_udp != NULL)
    {
      ENDUSER_SETUP_ERROR("dns_start failed. Appears to already be started (espconn_dns_udp != NULL).", ENDUSER_SETUP_ERR_ALREADY_INITIALIZED, ENDUSER_SETUP_ERR_FATAL);
    }
    state->espconn_dns_udp = (struct espconn *) malloc(sizeof(struct espconn));
    if (state->espconn_dns_udp == NULL)
    {
      ENDUSER_SETUP_ERROR("dns_start failed. Memory allocation failed (espconn_dns_udp == NULL).", ENDUSER_SETUP_ERR_OUT_OF_MEMORY, ENDUSER_SETUP_ERR_FATAL);
    }
  
    esp_udp *esp_udp_data = (esp_udp *) malloc(sizeof(esp_udp));
    if (esp_udp_data == NULL)
    {
      ENDUSER_SETUP_ERROR("dns_start failed. Memory allocation failed (esp_udp == NULL).", ENDUSER_SETUP_ERR_OUT_OF_MEMORY, ENDUSER_SETUP_ERR_FATAL);
    }
  
    memset(state->espconn_dns_udp, 0, sizeof(struct espconn));
    memset(esp_udp_data, 0, sizeof(esp_udp));
    state->espconn_dns_udp->proto.udp = esp_udp_data;
    state->espconn_dns_udp->type = ESPCONN_UDP;
    state->espconn_dns_udp->state = ESPCONN_NONE;
    esp_udp_data->local_port = 53;
  
    int8_t err;
    err = espconn_regist_recvcb(state->espconn_dns_udp, enduser_setup_dns_recv_callback);
    if (err != 0)
    {
      ENDUSER_SETUP_ERROR("dns_start failed. Couldn't add receive callback, unknown error.", ENDUSER_SETUP_ERR_UNKOWN_ERROR, ENDUSER_SETUP_ERR_FATAL);
    }
  
    err = espconn_create(state->espconn_dns_udp);
    if (err == ESPCONN_ISCONN)
    {
      ENDUSER_SETUP_ERROR("dns_start failed. Couldn't create connection, already listening for that connection.", ENDUSER_SETUP_ERR_SOCKET_ALREADY_OPEN, ENDUSER_SETUP_ERR_FATAL);
    }
    else if (err == ESPCONN_MEM)
    {
      ENDUSER_SETUP_ERROR("dns_start failed. Couldn't create connection, out of memory.", ENDUSER_SETUP_ERR_OUT_OF_MEMORY, ENDUSER_SETUP_ERR_FATAL);
    }
    else if (err != 0)
    {
      ENDUSER_SETUP_ERROR("dns_start failed. Couldn't create connection, unknown error.", ENDUSER_SETUP_ERR_UNKOWN_ERROR, ENDUSER_SETUP_ERR_FATAL);
    }
  
    return 0;
  }
  
  
  static void enduser_setup_dns_stop(void)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_dns_stop");
  
    if (state != NULL && state->espconn_dns_udp != NULL)
    {
      espconn_delete(state->espconn_dns_udp);
    }
  }
  
  
  static int enduser_setup_init(lua_State *L)
  {
    /* Note: Normal to not see this debug message on first invocation because debug callback is set below */
    ENDUSER_SETUP_DEBUG("enduser_setup_init");
  
    /* Defer errors until the bottom, so that callbacks can be set, if applicable, to handle debug and error messages */
    int ret = 0;
  
    if (state != NULL)
    {
      ret = ENDUSER_SETUP_ERR_ALREADY_INITIALIZED;
    }
    else
    {
      state = (enduser_setup_state_t *) calloc(1, sizeof(enduser_setup_state_t));
  
      if (state == NULL)
      {
        ret = ENDUSER_SETUP_ERR_OUT_OF_MEMORY;
      }
      else
      {
        memset(state, 0, sizeof(enduser_setup_state_t));
  
        state->lua_connected_cb_ref = LUA_NOREF;
        state->lua_err_cb_ref = LUA_NOREF;
        state->lua_dbg_cb_ref = LUA_NOREF;
  
        state->softAPchannel = 1;
        state->success = 0;
        state->callbackDone = 0;
        state->lastStationStatus = 0;
        state->connecting = 0;
      }
    }
  
    int argno = 1;
  
    if (lua_isstring(L, argno)) {
      /* Get the SSID */
      state->ap_ssid = strdup(lua_tostring(L, argno));
      argno++;
    }
  
    if (!lua_isnoneornil(L, argno))
    {
      lua_pushvalue(L, argno);
      state->lua_connected_cb_ref = luaL_ref(L, LUA_REGISTRYINDEX);
    }
  
    argno++;
  
    if (!lua_isnoneornil(L, argno))
    {
      lua_pushvalue (L, argno);
      state->lua_err_cb_ref = luaL_ref(L, LUA_REGISTRYINDEX);
    }
  
    argno++;
  
    if (!lua_isnoneornil(L, argno))
    {
      lua_pushvalue (L, argno);
      state->lua_dbg_cb_ref = luaL_ref(L, LUA_REGISTRYINDEX);
      ENDUSER_SETUP_DEBUG("enduser_setup_init: Debug callback has been set");
    }
  
    if (ret == ENDUSER_SETUP_ERR_ALREADY_INITIALIZED)
    {
      ENDUSER_SETUP_ERROR("init failed. Appears to already be started. EUS will shut down now.", ENDUSER_SETUP_ERR_ALREADY_INITIALIZED, ENDUSER_SETUP_ERR_FATAL);
    }
    else if (ret == ENDUSER_SETUP_ERR_OUT_OF_MEMORY)
    {
      ENDUSER_SETUP_ERROR("init failed. Unable to allocate memory.", ENDUSER_SETUP_ERR_OUT_OF_MEMORY, ENDUSER_SETUP_ERR_FATAL);
    }
  
    return ret;
  }
  
  
  static int enduser_setup_manual(lua_State *L)
  {
    if (!lua_isnoneornil (L, 1))
    {
      manual = lua_toboolean (L, 1);
    }
    lua_pushboolean (L, manual);
    return 1;
  }
  
  
  static int enduser_setup_start(lua_State *L)
  {
    /* Note: The debug callback is set in enduser_setup_init. It's normal to not see this debug message on first invocation. */
    ENDUSER_SETUP_DEBUG("enduser_setup_start");
  
    ipaddr[0] = '\0';
  
    if (!do_station_cfg_handle)
    {
      do_station_cfg_handle = task_get_id(do_station_cfg);
    }
  
    if(enduser_setup_init(L))
    {
      goto failed;
    }
  
    if (!manual)
    {
      ENDUSER_SETUP_DEBUG("Performing AP Scan to identify likely AP's channel. Enabling Station if it wasn't already.");
      wifi_set_opmode(STATION_MODE | wifi_get_opmode());
      wifi_station_scan(NULL, on_initial_scan_done);
    }
    else
    {
     enduser_setup_check_station_start();
    }
  
    if(enduser_setup_dns_start())
    {
      goto failed;
    }
  
    if(enduser_setup_http_start())
    {
      goto failed;
    }
  
    goto out;
  
  failed:
    enduser_setup_stop(lua_getstate());
  out:
    return 0;
  }
  
  
  /**
   * A wrapper needed for type-reasons strictness reasons.
   */
  static void enduser_setup_stop_callback(void *ptr)
  {
    enduser_setup_stop(lua_getstate());
  }
  
  
  static int enduser_setup_stop(lua_State* L)
  {
    ENDUSER_SETUP_DEBUG("enduser_setup_stop");
  
    if (!manual)
    {
      enduser_setup_ap_stop();
    }
    if (state != NULL && state->success && !state->callbackDone)
    {
      wifi_set_opmode(STATION_MODE | wifi_get_opmode());
      wifi_station_connect();
      enduser_setup_connected_callback();
    }
    enduser_setup_dns_stop();
    enduser_setup_http_stop();
    enduser_setup_free();
  
    return 0;
  }
  
  
  LROT_BEGIN(enduser_setup, NULL, 0)
    LROT_FUNCENTRY( manual, enduser_setup_manual )
    LROT_FUNCENTRY( start, enduser_setup_start )
    LROT_FUNCENTRY( stop, enduser_setup_stop )
  LROT_END(enduser_setup, NULL, 0)
  
  
  NODEMCU_MODULE(ENDUSER_SETUP, "enduser_setup", enduser_setup, NULL);
  